Physics— Concepts, Formulas & Shortcuts
- SI base units: metre, kilogram, second, ampere, kelvin, mole, candela.
- Newton's laws: inertia; F = ma; action and reaction — the third law explains rocket propulsion and gun recoil.
- Speed of light in vacuum ≈ 3 × 10⁸ m/s; speed of sound in air ≈ 343 m/s at 20 °C.
- Convex lens corrects hypermetropia (long sight); concave lens corrects myopia (short sight).
- A generator converts mechanical energy to electrical; a motor does the reverse.
- Echo is reflected sound; a minimum distance of about 17 m is needed for the ear to distinguish it.
Physics Practice Questions with Answers
Attempt each question first, then open the explanation. All 16 questions below are free to read and require no signup.
Q1.The SI unit of force is:
Easy- AJoule
- BNewton
- CWatt
- DPascal
Physics question 1 of 16+Show Answer & Explanation
Answer: B. Newton
Explanation: One newton is the force that accelerates 1 kg at 1 m/s².
Q2.The speed of light in vacuum is approximately:
Easy- A3 × 10⁶ m/s
- B3 × 10⁸ m/s
- C3 × 10¹⁰ m/s
- D3 × 10⁵ m/s
Physics question 2 of 16+Show Answer & Explanation
Answer: B. 3 × 10⁸ m/s
Explanation: Light travels at about 299,792,458 m/s, conventionally rounded to 3 × 10⁸ m/s.
Q3.The recoil of a gun when fired is explained by:
Easy- ANewton's first law
- BNewton's second law
- CNewton's third law
- DHooke's law
Physics question 3 of 16+Show Answer & Explanation
Answer: C. Newton's third law
Explanation: Action and reaction are equal and opposite, so the gun moves backward as the bullet moves forward.
Q4.The SI unit of electric current is:
Easy- AVolt
- BOhm
- CAmpere
- DCoulomb
Physics question 4 of 16+Show Answer & Explanation
Answer: C. Ampere
Explanation: The ampere measures the rate of flow of charge — one coulomb per second.
Q5.Long-sightedness (hypermetropia) is corrected using a:
Moderate- AConcave lens
- BConvex lens
- CCylindrical lens
- DBifocal lens
Physics question 5 of 16+Show Answer & Explanation
Answer: B. Convex lens
Explanation: A convex (converging) lens brings the image forward onto the retina. Concave lenses correct short-sightedness.
Q6.An echo is produced due to:
Easy- ARefraction of sound
- BReflection of sound
- CDiffraction of sound
- DAbsorption of sound
Physics question 6 of 16+Show Answer & Explanation
Answer: B. Reflection of sound
Explanation: Sound reflects off a distant surface and returns to the listener after a perceptible delay.
Q7.A device that converts mechanical energy into electrical energy is a:
Easy- AMotor
- BGenerator
- CTransformer
- DRectifier
Physics question 7 of 16+Show Answer & Explanation
Answer: B. Generator
Explanation: A generator (dynamo) uses electromagnetic induction; a motor performs the reverse conversion.
Q8.A barometer is used to measure:
Easy- AHumidity
- BAtmospheric pressure
- CTemperature
- DWind speed
Physics question 8 of 16+Show Answer & Explanation
Answer: B. Atmospheric pressure
Explanation: A barometer measures atmospheric pressure, which is why a sudden fall in reading signals an approaching storm.
Q9.The SI unit of energy is the:
Easy- ANewton
- BWatt
- CJoule
- DPascal
Physics question 9 of 16+Show Answer & Explanation
Answer: C. Joule
Explanation: One joule is the work done when a force of one newton moves an object one metre.
Q10.Which mirror is used as a rear-view mirror in vehicles?
Moderate- APlane
- BConcave
- CConvex
- DCylindrical
Physics question 10 of 16+Show Answer & Explanation
Answer: C. Convex
Explanation: A convex mirror gives an erect, diminished image and a wider field of view.
Q11.The phenomenon of splitting white light into its colours is called:
Moderate- AReflection
- BRefraction
- CDispersion
- DDiffraction
Physics question 11 of 16+Show Answer & Explanation
Answer: C. Dispersion
Explanation: Dispersion occurs because different wavelengths refract by different amounts.
Q12.Which of these is a scalar quantity?
Moderate- AVelocity
- BForce
- CSpeed
- DAcceleration
Physics question 12 of 16+Show Answer & Explanation
Answer: C. Speed
Explanation: Speed has magnitude only; the others have both magnitude and direction.
Q13.The unit of electrical resistance is the:
Easy- AAmpere
- BVolt
- COhm
- DCoulomb
Physics question 13 of 16+Show Answer & Explanation
Answer: C. Ohm
Explanation: Resistance is measured in ohms, defined by Ohm's law as volts per ampere.
Q14.Sound cannot travel through:
Easy- ASolids
- BLiquids
- CGases
- DVacuum
Physics question 14 of 16+Show Answer & Explanation
Answer: D. Vacuum
Explanation: Sound requires a material medium to propagate, so it cannot travel through a vacuum.
Q15.The force that opposes relative motion between surfaces in contact is:
Easy- AGravity
- BFriction
- CTension
- DThrust
Physics question 15 of 16+Show Answer & Explanation
Answer: B. Friction
Explanation: Friction acts along the surfaces and opposes their relative sliding.
Q16.A body in uniform circular motion has constant:
Difficult- AVelocity
- BSpeed
- CAcceleration
- DDisplacement
Physics question 16 of 16+Show Answer & Explanation
Answer: B. Speed
Explanation: The magnitude of velocity stays constant, but its direction changes continuously, so velocity itself is not constant.
Physics — Frequently Asked Questions
Which physics topics appear most often in competitive exams?+
Units and measurements, laws of motion, work-energy-power, light (reflection, refraction, lenses), sound, heat, and current electricity — together with the everyday applications of each.
Why does a gun recoil when fired?+
Newton's third law with conservation of momentum: the forward momentum given to the bullet is matched by an equal and opposite backward momentum of the gun.
Cleared the aptitude round? Now grab the role.
Preparation only pays off when you apply. Thousands of internships and fresher jobs across India are live on MyInternships.in right now — free to apply, no consultancy fees.